Vascular cognitive impairment （VCI） refers to a broad category of syndromes caused by the risk factors for cerebrovascular diseases， ranging from mild cognitive impairment to dementia， and it has diverse clinical manifestations， often with occult early signs. Neurocognitive scales that are widely used in clinical practice， such as Montreal Cognitive Assessment and Mini-Mental State Examination， are used as the evidence for evaluating VCI； however， their application is limited due to low specificity， low sensitivity， and subjective bias. As a new technique used in clinical practice in recent years， quantitative electroencephalography （QEEG） has been taken seriously by researchers due to its features of noninvasiveness， quantifiability， and real-time monitoring. Currently， an increasing amount of evidence has shown that the specific quantitative parameters of QEEG can help with the early diagnosis of VCI， and the commonly used parameters include relative power， slow wave ratio， paired derived brain symmetry index， EEG coherence， Lemple-Ziv complexity， and P300. Mild cognitive impairment （MCI） is the early stage of VCI， and the specific changes on QEEG for MCI patients mainly include increased slow wave power and θ waves and β waves ratio value， prolonged P300 latency， and reduced wave amplitude. Cerebral small vessel disease （CSVD） is one of the common subtypes of VCI and has occult clinical symptoms and slow progression， and thus it is often neglected by patients and medical staff. There are relatively few reports on related electrophysiological research， and it is currently believed that the simultaneous appearance of a large number of abnormal sharp waves and background changes on electroencephalography may indicate the exacerbation of cognitive impairment in CSVD. Post-stroke cognitive impairment （PSCI） refers to cognitive impairment triggered by stroke events， and studies have shown that δ waves， θ waves， β waves， δ waves and αwaves ratio value， and δ waves and θ waves ratio value， all have a certain significance in identifying PSCI. Furthermore， the application of QEEG technique can accurately differentiate VCI from other cognitive impairment disorders， such as dementia with Lewy bodies and Alzheimer's disease， and it can also be used to evaluate the efficacy of drug or other intervention measures in VCI patients. Therefore， as a new supplementary or alternative method， QEEG technique provides new directions and ideas for tracking the progression of VCI， distinguishing various cognitive impairments， and assisting in the development of treatment plans.